I'm wondering why the images were on the cards "a couple of days" in the first place?
It is STRONGLY SUGGESTED to get the images backed up on location:
That means copying the contents to a portable card reader or a laptop with a USB 2.0 reader on 2 physical locations (example: laptop HD and a $40 40gb USB2 hard drive or your original cards and the card reader or 2 card readers... doesn't matter how, HAVE 2 COPIES MINIMUM.)
If you don't have enough cards for the whole event, I suggest you make *2* backups of the photos as each card gets filled:
This means either have someone knowledgeable that you trust make the 2 copies on-site as you need them, and then possibly delete (thats delete, NOT format!) the cards before they return them to you, then when the storage medium is returned to you, reinsert into camera and format (even if empty). You *always* want your camera to do the formatting, NOT anything else.
The above being said, the price of storage medium is RIDICULOUSLY low today. 1.5 years ago, a 8GB Extreme IV card was $299US. Today, that same one is $75US and a 16GB Extreme IV is $99. That means... realistically, there is NO REASON why any professional should not have enough cards to do ANY event and even need to reuse a card twice on said event (yes that includes you wedding shooters who do 2500 shots a day... if you are getting paid for this, DO IT RIGHT! That means that if you need 10 cards a day... GET 10 cards!). Size: Depends on the camera. On my camera's highest setting, I get 320 pictures per 8GB which is what I would consider the smallest size adequate for my needs. Using HIGH quality cards, I have no fears using a 16gb card to get about 620-640 pictures per card. On a day where I shoot 2500 pictures, thats 4 (16GB) cards, and a reasonable ratio of # of cards to # of pics on each card. If I used the 8GB cards, that means that under similar circumstances, I would need 8 cards.
Now the counter to the "use a million small cards and change often", is that it is a lot easier to misplace and lose 8 cards than it is to lose 4. 4-6 cards per event is my preferred # of storage cards and I choose the size of the cards so that 4-6 cards gets me the # of photos that I need to hold to do an entire event.
When I was doing weddings, as I came close to filling a card, I would swap to an empty one and hand the filled one to an assistant, who would make 2 copies and then return an empty card back to me. If I did not have an assistant, I would have more cards and put the filled ones into a plastic waterproof container (aka a sandwich bag)and keep them on the inside breast pocket of my jacket or shirt or belt mounted holder/storage. For heaven's on a table somewhere or your girlfriend's purse, that is just there watching you work is NOT a safe place!
Even if your event was a 20 hour work day... your day is NOT finished until you've transferred the photos off the camera storage media and made *2* backups on 2 separate physical devices immediately upon coming home or to the office. Waiting "a couple of days" is just unprofessional and asking for issues to bite you. For me, my standards mandate that even waiting overnight is unacceptable. Backup NOW.
On your computer, have a couple of undelete and/or recovery programs available for your needs. Do a google, there are hundreds of apps, some free, some low cost and some high cost. Some manufacturers incude a CD with each card that is made to recover files from their media (SanDisk Extreme III and IV for example). Not all work the same way and some can recover photos that are not recoverable by another software.
Finally...
Things that can corrupt your camera storage media:
- using cheap cards... for a pro, INEXCUSABLE. Use the best or go home. The best quality cards now-a-days are very affordable. There are no excuses here.
- Over-filling a card. If you see you have room for 5-10 more pics, CHANGE the card. What you see is an estimate, not the exact amount! I change them when it is convenient or before I reach the 10-15 pics available mark at the latest (my personal preference).
- Removing the card from the camera before it has time to complete the entire write process. If you just did a burst of 20 high speed continuous shots, and realize that your space is low (or not), WAIT until all pics are written before removing the card. Most cameras have a "write activity light". Wait till this is off before removing the card. Some cameras can take several minutes to complete a huge burst. Wait... or be sorry.
Some may think that I am being hard... me, I think that I am not being hard enough and have softened or under-emphasized how I really feel about this topic. Common sense (the least common of all senses, it seems) rules here, and this is something that should almost NEVER happen to anyone (lost pics), if you follow the common sense suggestions mentioned here.
...well, not unless I use a smiley... lol
